Surface-dipole-directed formation of stable solid electrolyte interphase

• Published in: Cell reports physical science 2023-03, Vol.4 (3), p.101324, Article 101324
• Main Authors: Fan, Yingzhu, Li, Ruhong, Yi, Ruowei, Zheng, Lei, Wang, Jingshu, Huang, Rong, Gong, Zhongmiao, Li, Zhiyun, Qi, Jizhen, Liu, Xi, Fan, Xiulin, Shen, Yanbin, Chen, Liwei
• Format: Article
• Language: English
• Subjects: dipole; electric double layer; Li metal; solid electrolyte interphases; solid|liquid interface; surface
• ISSN: 2666-3864; 2666-3864
• DOI: 10.1016/j.xcrp.2023.101324

Solid electrolyte interphases (SEIs), which are formed by the decomposition of species in the inner Helmholtz plane (IHP) of the electrode surface, define the deposition behavior and cycling stability of Li metal anodes. Currently, the IHP is mainly tuned from electrolyte aspects. In this work, we report that the dominating species in the IHP could be readily controlled via surface dipoles. By self-assembling heteroatomic conjugated molecules on a Cu foil, we constructed a surface dipole that can increase the adsorption force of the Cu surface to anions, resulting in anion-rich IHP and an anion-derived SEI. The uniform nature of the self-assembled molecule layer and the robust anion-derived SEIs are conducive to uniform Li-deposited morphology, leading to a Li plating/stripping cycling Coulombic efficiency as high as 99.83%. This work sheds new light on tuning the electric double layer at the solid|liquid interface, which is of fundamental importance for the electrochemistry field. [Display omitted] •A surface dipole is obtained on a copper electrode by molecular self-assembly•The surface dipole results in an anion-rich inner Helmholtz plane•Anion-derived solid-state electrolyte interface generated under dipole direction•Lithium-less batteries show ultra-high Coulombic efficiency and long lifespan The construction of a stable solid electrolyte interphase (SEI) is vital for secondary Li batteries. Fan et al. demonstrate that degraded-anion-derived SEI could be readily obtained by surface dipoles, which regulate the dominated species in the inner Helmholtz plane, shedding light on regulation of the electric double layer at the solid-liquid interface.